I was ignorant about network commands, so I investigated what I used.
1.ping It is used to check if it is connected to the network or if a specific host is running. It sends a message to the other party, "Reply", and if the other party is alive, it will reply "I'm alive".
$ ping google.com
PING google.com (216.58.197.174): 56 data bytes
64 bytes from 216.58.197.174: icmp_seq=0 ttl=54 time=18.673 ms
64 bytes from 216.58.197.174: icmp_seq=1 ttl=54 time=18.657 ms
64 bytes from 216.58.197.174: icmp_seq=2 ttl=54 time=19.664 ms
64 bytes from 216.58.197.174: icmp_seq=3 ttl=54 time=17.743 ms
Ctrl + c
--- google.com ping statistics ---
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 17.743/18.684/19.664/0.679 ms
Explanation of the above execution results
4 packets transmitted <=Number of packets sent
4 packets received <=Number of received packets
0.0% packet loss <=Packet loss rate
round-trip min/avg/max/stddev = 17.743/18.684/19.664/0.679 ms <=The shortest time it took to send,Maximum time,Average time,Mean deviation
2.traceroute Display network routes. It is used when checking whether the network routing settings are correct.
$ traceroute dns.google
traceroute to dns.google (8.8.4.4), 64 hops max, 52 byte packets
1 buffalo.setup (192.168.11.1) 1.169 ms 0.911 ms 0.728 ms <=Like a home router
2 192.168.10.231 (192.168.10.231) 1.321 ms 1.918 ms 1.285 ms
3 fkc-mx480-bbbas05.qtnet.ad.jp (218.40.227.148) 2.624 ms 3.535 ms 2.993 ms <=QT net-like
4 * 211.9.102.37 (211.9.102.37) 3.830 ms
211.9.102.33 (211.9.102.33) 3.186 ms
5 61.203.192.241 (61.203.192.241) 2.853 ms 3.376 ms
61.203.192.249 (61.203.192.249) 3.569 ms
6 61.203.193.122 (61.203.193.122) 19.343 ms
61.203.193.126 (61.203.193.126) 18.152 ms
61.203.193.122 (61.203.193.122) 18.438 ms
7 61.203.192.177 (61.203.192.177) 102.486 ms 57.606 ms 19.654 ms
8 108.170.242.129 (108.170.242.129) 19.595 ms 20.212 ms
108.170.242.193 (108.170.242.193) 56.511 ms
9 66.249.95.155 (66.249.95.155) 24.191 ms
108.170.233.77 (108.170.233.77) 19.702 ms
72.14.233.221 (72.14.233.221) 19.364 ms
10 dns.google (8.8.4.4) 19.461 ms 19.845 ms 18.701 ms <=Arrived safely
3.host You can look up the IP address from the domain name, or conversely, look up the domain name from the IP address.
Ask for the IP address from the domain.
$ host dns.google
dns.google has address 8.8.4.4
dns.google has address 8.8.8.8
dns.google has IPv6 address 2001:4860:4860::8844
dns.google has IPv6 address 2001:4860:4860::8888
Ask for the domain from the IP address.
$ host 8.8.8.8
8.8.8.8.in-addr.arpa domain name pointer dns.google.
4.dig Get information about the host from the DNS server.
dig goole.com
; <<>> DiG 9.10.6 <<>> goole.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25027 <=Since it is NO ERROR, you can see that a normal response is returned
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION: <=Inquiry
;goole.com. IN A
;; ANSWER SECTION: <=Answer to inquiry
goole.com. 1403 IN A 217.160.0.201 <=IP address of the inquired host
;; Query time: 61 msec <=Time taken for inquiry
;; SERVER: 192.168.11.1#53(192.168.11.1) <=IP address of the server that made the inquiry
;; WHEN: Tue Dec 10 00:53:07 JST 2019
;; MSG SIZE rcvd: 54
You can also use the DNS server.
dig @dns.google google.com
<<>> DiG 9.10.6 <<>> @dns.google google.com
; (2 servers found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58341
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 299 IN A 216.58.197.174
;; Query time: 86 msec
;; SERVER: 8.8.4.4#53(8.8.4.4) <=The DNS server to use has changed
;; WHEN: Tue Dec 10 01:23:50 JST 2019
;; MSG SIZE rcvd: 55
5.ifconfig
A command to check the IP address assigned to a network interface such as Ethernet, or to assign an IP address.
$ ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384 <=Loop back localhost 127.0.0.1
options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP>
inet 127.0.0.1 netmask 0xff000000
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1
nd6 options=201<PERFORMNUD,DAD>
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280 <=Interface for IPv6 and IPv4 tunneling
stf0: flags=0<> mtu 1280 <=Interface for routing IPv6 packets to an IPv4 network
XHC20: flags=0<> mtu 0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 <= Ethernet0
ether 4c:32:75:97:**:** <=Mac address
inet6 fe80::410:c692:d02f:d432%en0 prefixlen 64 secured scopeid 0x5
inet 192.168.11.3 netmask 0xffffff00 broadcast 192.168.11.255 <=IP address
nd6 options=201<PERFORMNUD,DAD>
media: autoselect
status: active
p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304
ether 0e:32:75:97:ab:2f
media: autoselect
status: inactive
awdl0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1484
ether fa:49:90:3f:a8:bb
inet6 fe80::f849:90ff:fe3f:a8bb%awdl0 prefixlen 64 scopeid 0x7
nd6 options=201<PERFORMNUD,DAD>
media: autoselect
status: active
en1: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
options=60<TSO4,TSO6>
ether 6a:00:02:ea:6b:10
media: autoselect <full-duplex>
status: inactive
en2: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
options=60<TSO4,TSO6>
ether 6a:00:02:ea:6b:11
media: autoselect <full-duplex>
status: inactive
bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 <=Connect the virtual interface to an external network??
options=63<RXCSUM,TXCSUM,TSO4,TSO6>
ether 6a:00:02:ea:6b:10
Configuration:
id 0:0:0:0:0:0 priority 0 hellotime 0 fwddelay 0
maxage 0 holdcnt 0 proto stp maxaddr 100 timeout 1200
root id 0:0:0:0:0:0 priority 0 ifcost 0 port 0
ipfilter disabled flags 0x2
member: en1 flags=3<LEARNING,DISCOVER>
ifmaxaddr 0 port 8 priority 0 path cost 0
member: en2 flags=3<LEARNING,DISCOVER>
ifmaxaddr 0 port 9 priority 0 path cost 0
nd6 options=201<PERFORMNUD,DAD>
media: <unknown type>
status: inactive
utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 2000
inet6 fe80::a83c:cb87:4ddf:f50b%utun0 prefixlen 64 scopeid 0xc
nd6 options=201<PERFORMNUD,DAD>
utun1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
inet6 fe80::55d3:d20b:a62c:e19c%utun1 prefixlen 64 scopeid 0xd
nd6 options=201<PERFORMNUD,DAD>
6.telnet Use this when you want to check if the network service is running.
↓ I set up my own web server.
$ telnet 127.0.0.1 8887
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
GET /
HTTP/1.1 200 OK <=response
content-length: 7
accept-ranges: bytes
connection: keep-alive
content-type: text/html; charset=utf-8
HELLO <=Contents of html file
Connection closed by foreign host.
I was in great trouble when I was wondering if the web server was alive, where did it stop, or if the port was open, so I will continue to investigate.
Recommended Posts